• From June 1985 to September 1987, 202 adults were enrolled in a randomized, double-blinded study comparing ciprofloxacin (500 mg) with sulfamethoxazole and trimethoprim (160 mg/800 mg) or placebo for adults with acute diarrhea. All patients were treated on the day of presentation and received medication on a twice-daily schedule (every 12 hours) for 5 days. Bacterial isolates from these patients included 35 Campylobacter, 18 Shigella, and 15 Salmonella. Treatment at the time of presentation with ciprofloxacin compared with placebo shortened the duration of diarrhea (2.4 vs 3.4 days), and increased the percentage of patients cured or improved by treatment days 1,3,4, and 5. Similar significant differences for sulfamethoxazole and trimethoprim compared with placebo were not seen.